Influence of polymeric microspheres on the myocardial oxygen partial pressure in the beating heart of pigs

► Injection of labeled microspheres is an established method in animal models to analyze the capillary organ blood flow at different time points. ► Microspheres can lead to stenoses of the capillary lumen, which might affect tissue oxygen supply. ► Our study aimed to investigate the influence of repeated injections of two differently sized microspheres (ø = 10 ± 0.1 μm (M10) or ø = 15 ± 0.15 μm (M15)) from polystyrene into the left coronary artery on the tissue oxygen partial pressure (pO2) in the downstream supplied myocardium of Göttingen minipigs. ►The findings suggest to use microspheres with diameters not exceeding 10 μm for the coronary blood flow assessment.